The co-abuse of energy drinks with alcohol has reached epidemic levels in young adults. This combination encourages heavy binge alcohol use, and is associated with an increase in alcohol- related problems including severe intoxication, violence, sexual assault, and drunk driving. This co-abuse of caffeine and alcohol coincides with the introduction of energy drinks that heralded the consumption of high caffeine content beverages in children and young adults, who prior to the availability of energy drinks had limited exposure to high caffeine levels. Recently, a new inhaled form of caffeine (Aeroshot) was introduced into the U.S. market as a dietary supplement and could expose young adults to even higher levels of caffeine posing an even greater risk of co-abuse with alcohol than energy drinks. Aeroshot is a caffeine delivery device the size and shape of a lipstick case. By inhaling from one end of the tube a fine powder containing 100 mg of caffeine is deposited into the oral cavity and upper airway. How much and how fast caffeine gets into the body using this method of administration are unknown. These are critical questions, because the disposition of caffeine following administration especially during the crucial absorption phase is an important factor influencing abuse potential. Our overall hypothesis is that caffeine administration by inhalation results in more rapid absorption of caffeine and greater physiologic and behavioral effects than administration by oral solution. We plan to evaluate this hypothesis by completing specific aim 1) determine the plasma concentration-time profile of caffeine and its major metabolites after administration by oral solution and inhalation, and specific aim 2) determine the cardiovascular and mood effects of caffeine after administration by oral solution and inhalation. We expect the results from this study to provide important insight into the abuse potential of the Aeroshot device alone and in combination with alcohol. Our long term goal is to define the pharmacodynamics of caffeine- alcohol abuse and the pharmacokinetic factors contributing to high-risk alcohol use in young adults.